Darunavir is a second-generation protease inhibitor used for treating human immunodeficiency virus (HIV) infection. Co-administration of darunavir with the antiretroviral drug ritonavir was approved by the FDA in 2006 for the treatment of HIV patients who have already been administered with other antiretroviral drugs.
Darunavir is chemically named [(1S,2R)-3-[[(4-aminophenyl)sulfonyl](2-methylpropyl)amino]-2-hydroxy-1-(phenylmethyl)propyl]-carbamic acid (3R,3aS,6aR)-hexahydrofuro[2,3-b]furan-3-yl ester, and is represented by the following chemical structure:

Darunavir and processes for its preparation are disclosed in EP 715618, WO 99/67417, U.S. Pat. No. 5,968,942, U.S. Pat. No. 6,248,775 and in Bioorganic and Chemistry Letters, 8, 687-690, 1998.
Several pseudopolymorphic forms of darunavir are described in US 2005/0250845 including the ethanolate, hydrate, methanolate, acetonate, dichloromethanate, ethylacetate solvate, 1-methoxy-2-propanolate, anisolate, tetrahydrofuranate, isopropanolate and mesylate solvates of darunavir.
Darunavir ethanolate is marketed in the United States under the trade name PREZISTA® by Tibotec. PREZISTA® is available as an orange, oval-shaped, film coated tablet for oral administration. Darunavir monoethanolate solvate is a white to off-white powder with solubility of approximately 0.15 mg/mL in water at 20° C.
A new form of a compound may possess physical properties that differ from, and are advantageous over, those of other crystalline or amorphous forms. These include, packing properties such as molar volume, density and hygroscopicity; thermodynamic properties such as melting temperature, vapor pressure and solubility; kinetic properties such as dissolution rate and stability under various storage conditions; surface properties such as surface area, wettability, interfacial tension and shape; mechanical properties such as hardness, tensile strength, compactability, handling, flow and blend; and filtration properties. Variations in any one of these properties affect the chemical and pharmaceutical processing of a compound as well as its bioavailability and may often render the new form advantageous for medical use.
There still remains an unmet need for additional solid state forms of darunavir having good physiochemical properties, desirable bioavailability, and advantageous pharmaceutical parameters.